Abstract
According to a long-established theory, categories are defined in terms of a set of features. Entities belong in the category if, and only if, they exhibit each of the defining features. The theory is problematic for a number of reasons. Many of the categories which are lexicalized in language are incompatible with this kind of definition, in that category members do not necessarily share the set of defining features. Moreover, the theory is unable to account for prototype effects, that is, speakers’ judgements that some entities are ‘better’ examples of a category than others. These findings led to the development of prototype theory, whereby a category is structured around its good examples. This article reviews the relevant empirical findings and discusses a number of different ways in which prototype categories can be theorized, with particular reference to the functional basis of categories and their role in broader conceptual structures. The article concludes with a discussion of how the notion of prototype category has been extended to handle polysemy, where the various senses of a word can be structured around, and can be derived from, a more central, prototypical sense.
